4WD doesn't engage unless I swap connectots on vacuum solenoids
 

I recently had a mechanic drop the transfer case to address a leak. (1992 3.0 extra cab). Now the 4WD doesn't engage. No click, no indicator light on the dash. I can get the 4WD to work if I swap the the two connectors to vaccuum solenoids under the hood but still no indicator light on the dash. This has got to be something simple Any suggestion on where to start looking greatly appreciated,

Probably, but what?
Start here: https://web.archive.org/web/20120424...26addcontr.pdf
The A.D.D. relay doesn't look easy to get to (I've never worked on mine), so I'd start with my multimeter on the VSVs under the hood. You're looking for voltage to ground on each; it should change from one to the other when you shift the transfer case. You can also just check the A.D.D. indicator switch for continuity (accessible at the front diff), but it doesn't sound like that's your problem.

Good luck, and keep us posted with the result.

Thank you much for the link. Will the checks be the same for the manual trans?

It turns out that the male connecter was broken on the sensor that is on the transfer case. And by broken, I mean shattered with only the only the pins remaining. Apparently there is an expiration date on black tape electrical tape repairs. Who knew? Now with a new connector soldered in place, everything functioning properly. Thanks for the help!